1. Field of the Invention
The present invention relates to cover folders for sheets of paper, and in particular to binders for securing the sheets within the cover folders.
2. Description of the Prior Art
Patent application Ser. No. 343,677 filed Jan. 28, 1982 entitled "Cover Foldrs" by David Leahy, Lee Carlson, John Capezzuto and Warren Pitts commonly assigned with the present patent application, contains related and common subject matter.
Cover folders for holding sheets of paper are conventionally available in the form of folded sheets of either plastic or paper. These cover folders typically include a plastic or metal binder placed along the folded edge of the cover. Such binders are generally formed by two elongated panels that are joined along a common edge, with a narrow opening along the opposite edge of the binder through which a cover may be inserted. A typical cover folder of this prior art design is illustrated in part in FIG. 1.
Prior art cover folders have the disadvantage that when the cover sheet is opened and separated, even with only slight force, it tends to separate from its binder. In particular, there generally is insufficient friction between the binder and the cover to keep the two together thus requiring an adhesive or other binding element to ensure secure engagement. Additionally, when sheets of paper are inserted into the cover and the cover opened, the sheets of paper tend to slip from the binder. Other prior art cover folders contain fasteners which must be inserted through the binder, cover, and sheets of paper held therein. Use of such fasteners necessitates the need for holes along the cover edge as well as along at least one edge of the inserted sheets. Such holes are undesirable since the sheets tend to tear during normal handling. The use of fasteners makes it more difficult and time consuming for the user to insert and remove the sheets. Furthermore, the edge holes tend to detract from the appearance of documents containing them.
Accordingly, it is an object of the present invention to provide an improved report cover which is securely held in a binder without the use of external fastening devices. A related object is to provide a binder which securely holds the cover and inserted sheets even when the cover is opened.
Another object of the invention is to provide a folder of the type containing a binder and folded cover sheet wherein the cover sheet is readily insertable and removable from the binder.
It is a further object of the invention to provide a report folder which may be joined to other like folders to form a single unit of stacked report folders.